Are You Secretly "Obese?"

When it comes to obesity, you probably feel like you've heard it all. Well, here's a new idea for you: "Normal weight obesity."

OK, so you're thinking: "That's a contradiction in terms. How can someone be both 'normal weight' and 'obese?' "

It's a term coined by Mayo Clinic cardiologist Francisco Lopez-Jimenez, based on his provocative new research indicating that even though you may not be "overweight" according to your BMI you still may have an obese person's problems.

"Oh, great," you're probably thinking now. "I diet. I exercise. I've get my weight under control. And now you're telling me I'm still 'obese' based on some whole new definition?" Sorry to be the one to break it to you. But, yeah.

Let me explain.

First of all, you remember that BMI stands for body-mass index. It's calculated based on your height and weight. Anyone with a BMI over 24 is "overweight." Thirty or above and you're "obese."

BMI has gotten a lot of criticism, though. Super healthy people, like athletes, are often "obese" even though they're all muscle. Lopez-Jimenez and his colleagues suspected the opposite also might be true: People whose BMIs are normal may still be at risk.

They analyzed data collected by the federal government about more than 2,000 adults considered lean based on their BMIs. It turns out that more than half of them had too much body fat. For men, that means at least 20 percent of their body weight was fat. For women, it's at least a third.

And those who had too much fat were more than twice as likely to have the "metabolic syndrome," a cluster of risk factors such as high blood pressure, high cholesterol and high blood sugar usually associated with obesity. People with the syndrome are at high risk for diabetes and heart disease.

Lopez-Jimenez, who presented his research last week at the American College of Cardiology meeting in Chicago, told me he thinks his findings mean we can't just rely on BMI. He thinks we should be paying more attention to body fat, and where it is on the body.

That fits with other recent research. Last week another study linked big bellies with dementia. And earlier this week new research from the Nurses' Health Study at Harvard found women with a lot of fat around their waists were more likely to die early from cancer or heart disease even if their weight was considered "normal."